In microscopy many applications call for microscopes with a small and compact design. Thus, it is known that an initially vertical beam path from an object to be observed is deflected within the microscope body into the horizontal direction, in order to be able to arrange optical components, such as zoom systems, in a horizontal manner. Such a horizontal beam path can then be further deflected into the vertical, and if necessary again into a horizontal, direction. It is also possible to create diagonally running beam paths within the microscope body.
Such a deflection of beam paths is conventionally brought about by deflection elements which are designed either as prisms or prism systems or mirrors or mirror systems. Such systems for their part have a certain spatial extension, making the design of small and compact microscopes difficult. These problems arise in particular with stereo microscopes.
Ophthalmological microscopes are in themselves known. They have a main objective, a magnification system downstream of this and a binocular system with oculars. In order to provide a stereo microscope, in a magnification system which is, for example, designed as a zoom system a splitting of the beam path passing through the main objective into a number of beam paths can be performed. Further, ophthalmological microscopes are known which allow simultaneous observation of the object by a first user (main operator) and by a second user (assistant).
For intra-ocular surgery, for example in order to be able to microscopically observe the fundus or the vitreous areas near the fundus of a human eye, additional optics are needed on stereo microscopes. These comprise lenses which are placed upstream of the main objective (on the object side).
In the leaflet “SDI II, BIOM II” from Oculus Optikgeräte GmbH from 1998 and U.S. Pat. No. 4,856,872 such an additional optic is described. This additional optic has a lens arranged close to the object to be observed (ophthalmoscopy lens) and a lens arranged in the vicinity of the main objective (reduction lens).
From DE 41 14 646 C2 a solution is known in which an ophthalmology attachment for an operation microscope is accommodated in an attachment housing which can be positioned laterally in relation to the main objective. The attachment has an ophthalmoscopy lens, an optical system for erecting the image and a displaceable lens (correction lens) for focusing.
The image erecting system is needed because the additional optics reproduce the microscope image with lateral and vertical inversion and thus pseudo-stereoscopically in the observation. This means, amongst other things, that when considering the depth in the intermediate image generated by the ophthalmoscopy lens the front and back are inverted. In order to work in microsurgery, however, an erected, stereoscopically correct image is necessary. At the same time as the image erecting, therefore, in the operation microscope an exchange of the two observation beam paths (pupil exchange) must take place in order, during the stereoscopic observation, to avoid the pseudo-stereo effect that would otherwise occur. A particularly preferred embodiment of such an optical system for image erecting is known as the SDI (or, Stereoscopic Diagonal Inverter) system. Such a system is, for example, known from the previously mentioned “SDI II, BIOM II” leaflet from 1998. The use of such SDI systems, however, is associated with considerable disadvantages for the microscope system or the image quality of the microscope. In particular, the adaptation of the optical beam path from this additional system to that of a stereo microscope proves to be very involved. The result is frequently defective image quality and clipping of the field which is caused by inadequate mechanical adaptation of the SDI system to the microscope. Furthermore, the construction height of such SDI systems is detrimental to the ergonomic construction height of the microscope.
From DE 103 32 603 A1 in order to improve the abovementioned disadvantages the fashioning of an optical inverter system is known for erecting and for observation beam inversion of a pseudo-stereoscopic image with a deflection element with a focusing power or refractive power. This allows, in a simple manner, the construction height of the stereo microscope to be reduced compared with the customary solutions, since customary SDI systems can be dispensed with. Thus, the ergonomic construction height of the microscope can also be reduced in an advantageous manner.